There is known, in particular from EP Patent No 1846874, a smart card fabrication method wherein an assembly formed of an integrated circuit and conductive segments is placed on a substrate and at least one integrated circuit is introduced into the substrate. Several variants are proposed. In a first variant, the integrated circuit is pushed straight into the material forming the substrate, the latter being relatively hard since it has conductive paths on its surface. Penetration into the material is generally achieved by using heat to soften the substrate material at least locally. In a second variant, prior to inserting the integrated circuit, a housing is arranged in the substrate having dimensions which substantially match those of the integrated circuit or are slightly different therefrom. In a third variant, a housing is formed having larger dimensions than those of the integrated circuit and an adhesive substance is deposited in the housing, prior to adding the integrated circuit assembly and conductive segments; then a fitting device presses the integrated circuit into the adhesive substance which is spread out and pushed back into the space located between the integrated circuit and the wall of the housing.
Although possible to achieve, each of the variants described above has a drawback. The first variant faces the fact that the substrate is generally formed by a relatively hard plastic layer; which requires particular precautions during fabrication of smart cards and particularly requires the areas penetrated by the integrated circuits to be at least locally softened, to avoid damaging the integrated circuits. Further, once the card is finished, the integrated circuit is surrounded by a relatively hard material; which may cause excessive mechanical stresses on the integrated circuit during use of the card, in particular when the card is subject to bending or twisting. In addition to the last mentioned problem of the first variant, the second variant raises a fabrication problem since it requires high precision positioning of the integrated circuit relative to the housing prior to insertion therein. This is possible to achieve with available fabrication plants, but the production of smart cards is then more expensive. The third variant may overcome certain of the aforementioned problems, but it requires the localised administration of drops of resin in the substrate housings in the smart card fabrication site.